ECUs are control units typically installed in the engine compartment of a vehicle. The ECU typically controls many of the functions of the vehicle such as the fuel injector drivers, engine operations, etc., by controlling a series of actuators based on input from sensors.
Typical ECUs have a circuit board that is disposed in a housing. A cover, mounted to the housing, covers the circuit board. When a vehicle and thus the ECU are exposed to high altitudes, internal pressure can build up inside the ECU. In a sealed ECU where the cover is sealed with respect to the housing, such internal pressure may cause the cover to deflect outwardly, reducing the effectiveness of the sealing arrangement. Using a vent in the ECU could equalize the pressure inside the ECU, but this solution cannot be used when customer's demands a sealed ECU. Cover deflection can be limited by using a cast cover. However, a cast cover is expensive and very heavy.
Thus, there is a need in a sealed ECU to limit, in a cost-effective manner, deflection of the cover when internal pressure increases inside of the ECU.